Production of valuable hydrocarbons



Aug. 28, 1945. N. K. CHANEY ETAL PRODUCTIONy 0F VALUABLE HYDROCARBONS Filed Dec. 28, 194C 3 Sheets-Sheet l MMM/fafa@ N. K. CHANEY TAL PRODUCTION OF VALUABLE HYDROCARBONS Aug. 28, 1945.

Filed Dec. 28, 1940 3 Sheets-Sheet 2 .on 2: md 061? 0: 30019.92/ NO/.L

N. K. QHANEY E-rAL PRODUCTION OF VALUABLE HYDROCARBONS Filed Djec. 28, 1940 3 SheetS-Sheet 3 .Patented Aug. 28, v1945' stares PROD'UIION 0F VLUABLE EYDROCARBONS Newcomb Kft. Chaney, Meylan, Pa., and Edwin L.

Hall, Manchester, N. H., assignors to 'Ehe United Gas improvement Company, a corporation of Pennsylvania applesauce December as, me, sensi No. entre ir claims. (ci. ectecm This invention pertains generally to theproduction of valuable hydrocarbons from petroleum oil by pyrolysis and pertains particularly to the manufacture 'of relatively large quantities of ailrylated and/or alkenated aromatic hydrocarbons and particularly aromatic msm-forming hydrocarbons by such petroleum oil pyrolysis. Y By aromatic resin-forming hydrocarbons it is meant to include such compounds as styrene,

of burners such as pilot burners and the mal-` .functioning of automatic appliances.

appliance valve cricesy causiug'the extinction Likewise in the case oi motor fuels, the presence of resin-forming hydrocarbons is highly undesirable because oi their interference with the proper operation of internal combustion engines. This invention as distinguished from the proc- I esses of the prior art is directed to the production cfa relatively larger total quantity of the resin forming hydrocarbons particularly aromatic resin-forming hydrocarbons. y

More particularly stated they invention comprises (1) the selection of a petroleum oil capable on controlled pyrolysis of producing relatively large yields of allwlated and/or allrenated aromatic hydrocarbons including relatively large yields. of `arronfuatic resin formcrs, and (2) the bons lboiling above 200 C. at atmospheric pressure and comprising dead oil and heavy ters.

Normally in the manufacture of oil gas, pe-

troleum oil is pyrolytically decomposed at high' temperatures and frequently under conditions of reduced partial pressures resultingr from the presence of large volumes of other gases such as steam or water gas, the latterbeing .a mixture of carbon monoxide and hydrogen. The products 'range all the way fromhydrogen'and normally gaseous hydrocarbons vwhich are condensible with l. dimculty to materials of extremely low vapor l pressure, such as the lless volatile constituents of tar, for example, pitch. A considerable quantity of carbon may also be produced.

These prior art processes are conducted with either of two purposes in mind. namely, (1) the `production of large volumes of combustible gas o be distributed as city sas, or (2) the producion of motor fuel.` y

In both instances, the desideratum is to conduct, the decomposition of the petroleum oil so as to avoid the production oi large quantitiesof.

resin-forming hydrocarbons.

In the case of combustible ges for distribution, the ,presence of relatively large quantities of resin-forming hydrocarbons is highly 'undesir able since these hydrocarbons have a propensity to'form resins throughout the gas distribution system and are'responsible for the stoppage of gas' The use of water gas pyrolysis of said selected oil or a desired cut or cuts therefrom under controlled conditions to be set forth hereinafter.

It is found that the quantitative production oi the individual above-mentioned alkylated and/or alkenated aromatic hydrocarbons including arol' matic resin-forming 'hydrocarbons varies widely with the use of different petroleum oils, and that certain physical and chemical characteristics of a petroleum oil, or combinations of these chari acteristics, may be employed as indices to meas ure the ability of said petroleum oil to quantitatively produce these compounds under care-v fully controlled conditions of pyrolysis. f y

Still more particularly, a petroleum oil is se- ,lected which may be classed aspredominantly 4naphthenic as determined by any one or more of a number of chosen methods of classification to l be hereinafter more particularly set forth, for instance, by the method of classification described in Bureau of Mines Report of Investigationsai. 3379. f

f in carrying out the invention the selected oil is pyrolyticaily decomposed in vapor phase and in an atmosphere diluted preferably with a readily conden'sible gas, such as steam, which is preferably present in sumcient quantity to materially reduce the partial pressures ofV the oil vapors. Preferably the steamis supplied in ratio 5 of at least 2 parts of steam to 3 parts oi oil by weight.

in large" ,quantities` as a.

diluent is preferably avoided among other. reasons, because of its relatively high concentration of hydrogen. Thus, we prefer to restrict the presence of any blue water gas to below 30 cubic feet per gallon of oil pyrolyzed and more preferably to below 20 cubic feet per gallon of oil pyrolized, said 4culoic feet being taken as if measured at a pressure of 760 mm. and a temperature of 60 F.

Generally speaking, the preferred operating conditions are of a cyclic character such as is characterized by the conventional cyclic gas making processes, although other types of operation including continuous are within the broad concept of the invention.

.are such that in any given plane normal to the flow of materials, the materials throughout the` plane have previously had substantially the same opportunity to be heated and to undergo the alternate decompositions and synthesis which comprises cracking and which progress toward products of greater thermal stability unde'r the environment obtaining. y

Other conditions being xed, variation of any one of the following factors in the direction cited is considered to tend toward less homogeneity in the cracking operation: (1) decreased surface/volume ratio of the cracking vesselsbeyond the vaporizing zone; (2) `reduced atomization of the oil; (3) increased impirgement of oil on highly heated surfaces prior to vaporization; (4) increased concentration of the oil vapors; (5) decreased turbulence; and (6) increased space velocity except as effecting turbulence.

In addition to relative homogeneity of cracking which as defined would permit wide changes in cracking conditions during a cycle, it is preferred that the cracking conditions also be what is termed herein relatively uniform during the cycle. v

In a cyclic operation in which oil cracking chambers are heated during a heating period and the stored heat utilized during the cracking period, the quantity of oil gas producedV (and the yields of the desired products) per gallon of oil during any individual oil-cracking run will vary somewhat as the temperature of the cracking chambers decreases during said run. The degree of variation will depend among other factors, upon the length of the oil-cracking run, the oil and steam input rates, the presence or absence of supplementary heating during the run, the quantity of heat storedduring the heating period and the character of the heat storage material.

Very large swings in oil gas production during a cycle are not preferred as any swing in oil gas production during a cycle necessitates a departure from the optimum conditions within the range of the swing Land, makes the cracking less uniform over the cycle. n

In cyclic operation, other conditions being equal, swings in oil gas production during `the cycle may be reduced by reducing temperature swings during the cycle which is favored by use of a relatively short cycle andi/or by the employmenl of highly conductive heat storage material.

Therefore, the environment 'of oil pyrolysis hereunder is advantageously arranged to provide not only relatively homogeneous cracking but also relatively uniform cracking.

A convenient measure of the homogeneity and uniformity of the cracking operation is the relation between the sulfonation residuel and the free carbon in the condensate from the gas', as will hereinafter appear.

Sulfonation residue is a measure of the normally non-gaseous paramnes and naphthenes surviving the cracking operation, and hence, high sulfonation residue is an indication of light cracking. Free carbon, on the other hand, is an end product in the pyrolysis of hydrocarbons and, hence, high free carbon indicates severe cracking.

High sulfonation residue together with high free carbon indicates that both light and severe cracking have taken place during the cycle and, hence, is an indication either of great lack of homogeneity of cracking, ,0r of great lack of uniformity of cracking, or both.

inasmuch as the determinations of sulfonation Aresidue and free carbon depend upon the methods of analysis employed, detailed descriptions of the analyses used herein will be given hereinafter and herein when the terms -sulfonation residue and free carbon are employed, they refer to the determinations obtained 'by said methods of analysis or by equivalent methods.

The present invention includes in addition to relatively homogeneous cracking and relatively uniform cracking the adjustment of the oil pyrolyzing environment including such factors as (l) temperature, and (2) effective time 0f contact to obtain a desired intensity 'of cracking. Intensity of cracking is conveniently measured by the volume of residual oil gas" produced per gallon of oil pyrolyzed, although any other suitable method may be employed or devised.

In accordance with this invention the oil pyrolyzing environment is such that per gallon of oil pyrolyzed the volume of residual oil gas" produced is maintained between 40 and 65 cubic feet taken as if measured at a pressure of '760 mm. and a temperature of 60 F., and preferably between 45 and 60 cubic feet under the same conditions of pressure and temperature.

Other conditions being the same, increase in either (l) temperature or (2) effective time of contact, or both, increases the volume-of residual oil gas per gallon of oil, and vice versa.

Residual oil gas" is defined as the'uncondensed nal gas after removal of substantially all water vapor or after correction for the presence of water vapor, and after the removal of substantially all hydrogen sulfide or4 after the correction for the presence of hydrogen sulde (unless the oilis low in sulfur content in which case the hydrogen sulfide isnegligible for calculation of residual oil gas), and after removal of substantially all hydrocarbons having more than three carbon atoms', or after correction for the presence of such hydrocarbons having more than three carbon atoms, and after correction for the lof contact.

4 Provided conditions oi (l) relatively geneous cracking and (2) relatively uniform assegna i The oil gas remaining after the above removal of or correction for hydrocarbons having more than three carbon atoms and after correcting for the presence of gases other than oil gas will be referred to herein and in claims as residual oil eas." Various procedures for the control of temperature in cyclic gas-malnng sets are well understood by the skilled gas-maker.

y These include (l) adjustment of the length of the blast run:

(3) adjustment oi the rate of fuel consumption during the blast run; (3) adjustment of the V length of the blast run with respect to the gasmaking run or runs; (4) adjustment of the length of the purge or purges; (5)y adjustment of the volume of steam or othergas used for purging; (6) adjustment of the length of the cycle; (f7) the use ci a reverse run or runs and the .adjustment oi theirlength; (8) the use of a reverse purge or .purgesz (9) the use of auxstance, as truevtemperature of lthe oil vapors and` gas; the edective time of contact, the concentration of oil vapors, the presence of catalysts and possibly other environmental conditions, it is /extremely diilicult of measurement by any means available at the present time other than based upon t1 .e oil-gas produced. The true temv perature, for example,` may vary from the observed temperature according to some function of the factors influencing effective time of contact, which in turn may vary from calculated time of contact depending on functions of space velocity, turbulence and the surface-volume rela- -tionships of the cracking vessels. True temperailiary heating means; (l0) adjustment of, the I point of entry of secondary air and any tertiary air during the blast '.v-and so for-th.

Time oi contact may be controlled by various factors, one of' which is, of course, the dimensions including cross-sectional area, free space and length of the gas-melting path of the set. ln a given set the length of the gas-making path is more or less fined and the seme applies to the diameters of the various parts thereof such as the diameter of the interior of'the carburetter,

' the diameter of the connection between the carburetter and the superheater, and the "diameter of .the superheater. With a. given oil and steam rate the time of contact may be increased and decreased with increase and decrease resc- 'tively of the free space through which the vapors new, for example, by adjusting the quantity and arrangement of the checkerbrick employed.

Time of contact may also be adjusted lovedjustine the oil rate or tlNteam rate, or both as will be obvious since the larger'the combined volume of the gases passing through the set the shorterfthe time of contact and viceversa.

The rate at `which the oil'is vaporized in the y set, the rate at-which the oil is cracked, and the degree to which the oil is cracked are also important factors. Then too, the point or points of oil admission and the'pcntior points of steam admission are tb be considered.

Thus it will be seen that, although any exact mathematicalLdetermination of time of contact would be extremely involved, the control of .the oil'and steam rates, the control of the point vor points oi entry ci oil/and steam, and the controlo the amount andarrangement of checkerbrich. each alone or in combination, affords to the skilled gas-maker a fairly exible control of time All rsuch factors will be well understood by the skilled gas-maker, making it possible for him, upon becoming familiar vvlth` this invention, to readily .adjust the operation of his set to yield residual oil gas within the ranges in volume speciiicaily set forth above.

ture may also vary from observed temperature because of factors involving the pyrometers ecn-f ployed and their positions in relationship tothe lining or other' heat storage materials in the cracking vessels. It is obvious that many permutations of these actorsmay be made.

However, if lthecraclring is (l) relatively homo= geneous-and (2) relatively uniform, the volume of "residual oil gas as above donned, is. e. meas--v ure which correlates these environmental factors and gives a convenient andaccurate index oi' (3) the intensity oi cracking.

It is as such an index that it is employed herein.

`'l'he specic volumes oi residual dil gas per gallon of oil recited have no utilitvper se except as a measure oi a range of intensity of cracking, just as certain` heights of mercury in. a thermometer-may have no utility except as a vmeasure of a range oi temperatures.

Il the cracking is not (l) "relatively homogeneousfand not (2) "relatively uniform, the volume ci residual oil gas per gallon ot oil pyrolyzed is not an accurate measure of (3) the intensity of cracking as the gas may then be corn- A.posed of large portions of highly cracked material and large portions of lightlycracked material.

' To summarize, broadly speaking our invention comprises pyrolyzing (l) a "selected oil under conditions of (2) relatively homogeneous crack ing and (3) relatively uniform cracking, and with (d) the intensity of cracking" vsuch'that (5.) the "residual oil gas falls within the range above given.

The selected oil is predominately naplithenic .as dened by one or more of the means to be hereinafter more' particularly described.

Relatively homogeneous cracking" conditions and relatively uniform cracking conditions are deiined by the relationship between sulfonation" residue and "free carbon, which relationship will also be hereinafter more particularly de-l scribed and illustrated in the drawings. Residual oil gas determinesthe "intensity of cracking" and means for determining residual oil gas will also be. hereinafter more particularly i described.

For convenience, the invention will be further illustrated in connection with the drawings which form a part of this specification and which show a chart useful for determining thereiationshipl between sulionation residue and free carbonl and illustrate apparatus in which the invention may,

be conveniently perfumed, and in which; Figure l shows an elevation partly in section, diagrammatically illustratina a cyclic gas-makillseti' fFigure 2 shows curves ,defining sulfonation residue-free carbon relationships; and

Figures e and 4 snow a. aow sheet mustraune the recovery or materials from the gas.

Referring to Figure l-this ligure illustrates diagrammatically apparatus in which the invention may be performed and comprises a cyclic gas-making set which may beI conventional.

l indicates af generator, 2 is a carburetter, l is a superheater. and I a wash box. The generator l is provided with a burner generally indicated at 5, with means for supplying uid fuel such as tar, generally indicated at 8, and with means y for supplying air for combustion of the fuel generally indicated at 1. The generator may be provided with secondary air supply means as at 8. 9 indicates checkerbrick arranged -above the combustion space I0. il, I2, and I3 are steam supply pipes.

'I'he generator I is connected at its upper portion to the `upper portion of the carburetter 2 by connection I4. The carburetter is illustrated as devoid of checkerbrick and is provided with oil supply means I5 provided with a nozzle I6 capable of finely at'omizing the oil.

The carburetter 2 is connected at its base with the base of the superheater 3 by connection I1.

The superheater 3 is shown provided with the checkerbrick indicated conventionally at I8. Offtake I9 provided with valve 20 leads from the top of. the superheater to the wash box d, from Whenceconnection a provided with valve 2| leads to condensate recovery equipment and a gas relief holder (not shown) The superheater is further provided with a stack valve 22 and may be provided with a steam supply means such as steam pipe 23. Air supply means such as 2t may be provided for admittin tertiary air to the superheater.

The generator I may be provided with the gas offtake 25, provided with valve 25, and leading from the lower portion of the generator I to the wash box 4.

The refractory linings of the carburetter chamber and the superheater indicated at 2 and 28 respectively, as well as the checkerbrick such as in thesuperheater may if desired beof carborundum or other highly heat conductive material instead of the clay fire brick customarily employed for this purpose. The use of relativevly highly heat conductive refractory material, an

outstanding example of which is carborundum or v silicon carbide, is especially advantageous from Athe standpoint of obtaining uniformity of cracking since among other things the swing in temperature during any given cycle is thus considerably reduced as compared to the swing when clay fire brick is used.

The carburetter may be provided with check- .erbrick as well as the superheater. Checkerbrick in lthe carburetter if employed are preferably fined rather than staggered to decrease the percentage of liquid oil coming into contact with heated surfaces prior to vaporization. An empty carburetter functions very satisfactorily in this respect. A

On the other hand,`checkerbrick or its equivalent is definitely preferred in the superheater. v Thus it is .preferred to provide a relatively low surface/volume ratio in the oil vapcrizing zone assavve through the carburetter to the superheater by way of connection I'I. Tertiary air may be supplied through air supply means 24, if desired. The combustion products pass through the superheater and through the stack valve 22 to atmos phere or to a waste heat boiler (not shown). During this operation, the stack valve 22` is open and valve 26 is closed.

This operation, termed the blow.vl heats an stores heat in the checkerbrick and lining of the generator, the lining of the carburetter and the checkerbrick and lining of the superheater.

The tar may then be shut oil? and a short air I purge made by air admitted through air supply means l, followed by a short steam purge with steam supplied to the base ofthe generator as at i8. The purged products pass out4 of the set through the stack valve 22.

After the set is purged, and with the stacl:`

valve 22 closed, valve 28 closed, and valves 20 and 2| open, petroleum oil selected as previously and hereinafter further described, is admitted to the carburetter top and finely atomized by the nozzle IB into the void space of the carburetter. Simultaneously, steam is admitted to the generator through thesteain supply i3 in the generator base, heated in passage through the generator checkerbrick and passed into the carburetter top by way of connection It. A portion or all of the steam may be admitted through the steam supply means l2 at the generator top above the checkerbrick, instead of through i3 at the bottom, and/or the temperature of the steam may be controlled by proportionlng the quantities admitted to the two portions of the generator.

The oil is vaporized in the cuiburetter in the presence of the superheated steam from the generator, the quantity of steam being sucient to materially reduce the partial pressure of the oil vapors. y

The vaporized oil and steam pass down through the carburetter and into the superheater through connection I'I.` Some cracking may take place inthe carburetter.

From the :base of the superheater the vaporized oil, steam and partially cracked vapors' pass upward through'the superheater checkenbrick in and a relatively high surface/volume ratio in the cracking zone.

Other fluid fuel than tar may be employed for heating the 'generator i, such for instance, as oil or gas. Further, the generator maybe provided with a grate and solidr fuel burned thereon for heating instead'of fluid fuel, if desired.

Thermocouple's such as the shielded thermo- .couples 28, 30, 3l, I2 and 33 may be provided which the desired pyrolysis is completed.

The reaction products and steam pass through connection I9, the wash box d, and connection 2li to a relief holderl (not shown) and thence f through condensing or other apparatus (not` shown) for the removal of the desired products from the gas.

After this-operation, termed the run, the oll admission may be discontinued and the reaction products purged from the set by steam admitted to the generator, theA reaction products beingvv purged into the relief-holder through the wash box.

The cycle may .then be repeated.` The above cycle is merely illustrative, it may be verygreatly supply means 23. In such case, the stack valve 22 is closed, valve20 is closed and valve 26 open.

The steam or steam and oil vapors and reaction products pass reversely through the superheater,

,s carburetter and generator and through connection 26 to the wash box and to the relief holder (not shown).

The uid fuel burner as a means of providing heat during the blow is preferred, but recourse might be made to the use of a solidfuel bed as in the conventional water gas generator, with the difference that it is preferred ,not to pass any large quantity of water gas through the carburetter and superheater during the oil cracking period. Other means for superheating steam for the 'process might be then employed or saturated steam employed. The use of superheated I steam, however, is preferred as it reduces the heating load on the canburetter.

During the blow, the operation is conducted to obtain the desired distribution of heat throughout the carburetter and super-heater.

` The following table will illustrate a typical swing in temperature at various points in a given set during a typical blow in the process of the invention. The temperatures were determined by the standard shielded type of thermocouple.

Table Temperature Tem rature Point in set F, start of F.pnd of blow blow Carburetter top 1, 405 1, ess Carburettor m1ddle l, 415 1, 065 Superheater base 1, 455 l, 545 Superheater middlel, 4 l, 500 Superheater top.. 1,458 l, 472

The temperature gradient throughout the set will vary with operating conditions and the nature and size of the set and the set lining and checker-l brick or other heat storage material.

In the case of set lining and other refractory material present, this is :in a measure associated with the relative heat conductivity thereof. For instance, thesubstitution o f refractory brick made of silicon carbide for refractory brick madeof ordinary fire clay will shift the temperature gradient of the set and other conditions 'being equal will reduce the temperature swing throughv out the cycle.

The temperature gradient naturally set up by the blow may be modified prior tothe` run by the injection of steam or other fluids vto the top of the carburetter and/or the base and/or top of the superheater and/or to the generator. it may be employed to remove peak temperatures. Reference is made4 to copending application Serial Number 191,441, filed February 19, 1938, by Edwin theprincipal object is the production of motor fuel.

The temperatures given above are purely illustrative in character and the temperature conditions as well as other conditions governing pyrolysis of the oil will vary with differentitypes of operation or equipment.

As previously pointed out, having selected a predominantly naphthenic oil, its pyrolysis is controlled by the gas maker, (modifying the interior of his set in accordance with the* above observations if he ilnds it necessary or desirable), such that (l) the relationship between sulfonation residue and free carbon does not exceed certain maxima and (2) the residual oil gas falls within the range given.I The relationship between sulfonation residue and free carbon determines (a) L. Hall, now Patent 2,372,197, dated March 27,

The point or points of introduction of the, loil may vary in different gas making equipment, from those chosen for illustration.

A carburetter devoid of checkerbrick is pre-- ferred for use in vaporizing the oil, but checkerbrick may be employed therein. The oil whether coming into contact with refractory surfaces in significant quantity or not is subjected to the temperatures of the carburetter and superheater with the steam and is decomposed in a manner essen relatively homogeneous and (b) relatively uniform cracking conditions and the residual oil gas determines (c) the intensity of cracking.

Since determinations of sulfonation residue and free carbon may vary somewhat with the methods of analysis employed, detailed procedures of analyses for these respective factors will be given herein, it being understood that values for sulfonation residue and for free carbon as expressed in the claims are to be determined by th'ese de.-` taled procedures; or their'equivalents for definitive purposes, and that other yardsticks might be devised for the same purpose without departing from the invention.

An overall sample of the tar (wet) resulting from the pyrolysis of a known quantity of oil and obtained by condensation from the resulting gas by bringing the gas -down to 'a temperature ofv I' present, sulfonation residue is determined upon the hydrocarbon distillate obtained, and is expressed as per cent of the original oil by volume. Free carbonl is determined upon the dry residual tar and is expressed in per cent of the original oil by weight. f

Free carbon determination is as follows.

'Determination of free carbon y Free carbon is determined in the manner described in The Gas ChemistsHandbook, 3rd edition, 1929a publication of the American Gas Association, pages 4215 and 426.

Sulfonation residue determination is as follows.

Determination of sulfonaton vresidue 250 ml. sample'of the above hydrocarbon distillate is shaken with 5% by volume (12.5 mls.) of 94% H2804 in a 500 m1. separatory funnel.

The acid is gradually and cautiously added and the temperature kept lbelow 25 C. by immersing the funnel in ice water when necessary.

After the reaction is completed the contents of the flask are transferred in approximately equal portions to each of two small separatory funnels (150 ml. Squibb separatoryiunnels).

The acid-washed oil is then centrifuged in thel smaller funnels for approximately five minutesat 500-600 R. P. M. 'using a laboratory centrifuge adapted to accommodate these funnels.

v The acid sludge is run of! slowly from each fun- Q -tially` differentvfrom the decomposition of cil. nel intov 200 mls. ofice water contained in a beaker. The acid sludge will sink to the bottom of the beaker and disperse into the water when wash water run olf.

The oil is then washed with two successive portions of by volume of 20% KOH solution followed by centrifuging for two minutes at 50G-600 R. P. M. and separation of the alkaline solution.

A final wash of 5% by volume of Water is made followed by centrifuging for two minutes at 500- 600 R. P. M. and separation of the wash water.

The oil is dried by adding a few granules of 4- mesh anhydrous calcium chloride, and flltering, and the volume of dry oil measured.

100 mls. of the washed and dried oil are distilled in the following manner. The oil is put in a 200 ml. round bottom Pyrex boiling flask.l The flask is then connected with a small Hempel distilling tubeusing a cork stopper. 'I'he top of the distilling tube is fitted with a two-hole cork stopper containing a thermometer (-5 C. to +360 C. in 1 C. intervals, 75 mm.immersion) and a drawnout capillary tube extending to the bottom of the flask. The purpose of the capillary tube is to admit a small stream of air during vacuum distillation for the purpose oi' preventing bumping.

TheI outlet of the Hempel distilling tube is connected to a Liebig condenser. The outlet of the condenser is connected to a Bogert distilling receiver. The pressureat which the vacuum distillation is conducted is regulated at the outlet of the Bogert receiver by means of a suitable type needle valve.

w Any suitable vacuum pump may be used to reduce the pressure to 30 mm. mercury for the nal distillation.

Distillation is made at two pressures-(a) oil boiling up to 160 C. is distilled 0H at atmospheric pressure, and (b) higher boiling fractions are distilled at 30 mm. mercury pressure and the-distilper cent free carbon as above determined and defined.

The area to the lef-t and below curve A embraces the relations between sulfonation residue and free carbon defining relatively homogeneous and relatively uniform cracking conditions hereunder.

More preferably cracking conditions are selectand free carbon which define relatively non! homogeneous and/or` relatively non-uniform cracking conditions hereunder.

The formulae for curves A, B and C are as follows:

Curve A X2-3(y-0.03) 0.05 Curve B X23(y-0.03) :0.03 Curve C X23(y-0.03) =0.01 y

in which .r=per cent free carbon as above described and latin stopped when the temperature reaches v If the material being distilled shows any of the characteristic signs of decomposition before the temperature of 270 C. is reached, the distillation is discontinued. 'I he oil boiling up to 160 C. at atmospheric pressure is removed from 'the Bogert receiver before startingY the vacuum distillation. Low pressure steam should be available for use in melting any naphthalene accumula-tions which may cause stoppages in the condenser tube.

The two distillates are mixed and .the total volume recorded. Sulfonation residue tests are made on 10 ml. portions of the mixture in a Babdefined y=per cent sulfonation residue'as above described and defined.

Moving to the rightv from Ithe area to the left and below curve C, to the area between curves C and B and thence to the area between curves B and A, relationships of sulfonation residue and free carbon are encountered which progressively denne less homogeneous and/or less uniform cracking conditions. To the right and above curve A, these relationships are such as to nolonger define relatively homogeneous and relatively uniform cracking hereunder.

As previously stated the present invention includes adjusting the oil pyrolyzing environment including such factors as temperature, effec-tive time of contact and concentration of oil vvapors so that per gallon of oil the total volume of'oil gas produced after the removal of substantially allwater vapor, or after correction for the presence of water vapor; and after the removal of substantially all hydrogen sulfide, or after the correction for the presence of hydrogen sulfide (unless the oil is low in sulfur content, in which case the hydrogen sulfide is negligible for calculation of residual oil gas); and after removal of substantially all hydrocarbons having more than three carbon atoms, or after correction for the presence of hydrocarbons having more than three carbon atoms; and after correction for the pressence of gas not derived from the oil cracked such as air, combustion gases from fuel used for heating and any water gas which may be present, is maintained between 40 and 65 cubic feet taken as if measured at a .pressure of '160 mm. and a temperature of F., and preferably between 45 and 60 cubic feet under the same conditions of pressure and temperature.

The volume of residual oil gas may be calculated as follows:

Determination of nesiual oil gas The gas may be metered and sampled at any convenient stage in its condensation and purlflby volume, according to methods set forth in the analysis apparatus or its equivalent. This apparatus has been described in Industrial and Elfigi-` neering Chemistry, analytical edition, March 15, April 15, and May 15, 1933, and its use in hydrocarbon gas analysis'is very well known to those skilled in the art.

By the above means, the dried sample may be divided into four portions: (1) containing Ha, Nn, O2, CO, CO2, CH4, and any Hrs, CS2, HCN, SO: NH3 present, (2) containing Cz hydrocarbons such as C21-I4 and C2He, (3) containing Ca hydrocarbons such as 03H6 and CaHa, and (4) containing C4 hydrocarbons and hydrocarbons oi higher earbon content. The per cent by volume relationship of these portions to the original undried gas may be readily calculated.

Another measured portion of the original sample may be analyzed for HrS according to methods described in the above mentioned Gas Chemists Handbook. From the analysis the percentage o' His by volume in the gas as metered may be readily calculated.

Portion 1 may be analyzed for Hi, N2. Oz, CO and CO2, by means of the well known Hempel i apparatus or its equivalent by methods described in the above mentioned Gas Chemists Handbook or their equivalents which methods include the initial removal of Hrs and the percentage by volume of these constituents in the gas as metered Ha between water gas and oil gas is as follows:

The above apportionmentof CO2 and Hz is known to be approximate as the percentages of CO andlCOz in water gas vary with the temperature of its generation. The approximation is however suillciently accurate for the purpose vof calculating the residual oil gas.

'rhe csr, sor, HCN, and NH3 cententsfef 'the gas may be assumed to be negligible in the /calculation of the vresidual oil gas unless these mal tent er the gas prier te Hrs removal might not be negligible vin the calculation of residual oil gas and therefore'if the gas be metered and sampled prior to HaS puriilcation, the Has content should be determined and the volume of HzS deducted in calculating the residual oil gas.

From the volume of total gas in cubic feet as metered and' the volume of oil pyrolyzed in its manufacture, ingallons, the .cubic feet 'of total' gas perlgallon of oil under the pressure and temperature conditions of metering may be readily calculated. The volume of total gas per gallon of oil is for convenience calledA V1.

- VlX% air and/combustion l'==c1bic feet oi air-and combustio gaies per gallon of oii= Vr V|X% oi water gas-cubic leet` oi water gas per gallon of oil Vs VlX% Ci hydrocarbons and higher=oubic feet oi Crhydrocarbons and higher per gallon of oil V4 *V|X% water vapormcublc feet of water vapor per gallon of oil= Vg VlX% Hrs-*cubic feet of H1B per gallon o! oilw Ve V, Vr+ Vr-l- Vri- Vr-l-Va =cubic feet o! residual oil gas perl lion oi oil under the pressure and temperature conditions of meter g= Vr .If P=gss pressure as metered -in nlm. Hg and 'l=gas temperature as metered in F. absolute.

V`X Ix5l9. residusl oil gas in cubiclieet per gallon oi oil at a 780 T pressure 01760 mm. and a temperature of 60 F.

If the gas 1s-'metered and analyzed after the usual Hrs purification Vs need not be deducted sharp separation between hydrocarbons of three The method of apportionment of the C02 between combustion gas and water gas and of the terials are known tobe present in significant. j

quantities which is usually not the case. f

Il' the gas ,be metered and sampled after the usual HaS puriiication, the HzS may be assumed to be negligible for this calculation also, as the usual HrS purification removes practically all of the H28 as well as HCN and S011 Il the oil employed is not high in sulphur content, the Hi8 may be negligible for the calculation When employing low sulphur oils the H2B concarbon atoms and hydrocarbons of four carbon' atoms is not found to be essential, since even 'if a` fair percentage of the hydrocarbons of four carbon atoms is left in the gas the total volume of residual oil gas is not greatly increased.

Due to the dilculty of condensing hydrocarbonsof three carbon atoms or lower, no large portions of these hydrocarbons will ordinarily condense along with the hydrocarbons of four carbon atoms and higher.

As'an example of homogeneous and uniform cracking-the following is givenr y A Example v1f A cyclic cracking operation was carried on .in

"e three shell set connected in series similar to that diagrammatically illustrated in Figure 1.

The carburetter and superheater were 2 9" in internal diameter- The carburetter was approxiconnected at their bases by a connection .1 0"

tent of the gas prior to H28 'purification may be of the order of 50 grains per 10o cu. ft.equiva1ent internal diameter and 2' s" leng.- Beth. earbln-etter and superheater were lined with Carborundum refractory brick. The carburetter was devoid of checkerbrick. The superheater was provided with 29 l courses of Carborundum checkerbrick of standard size .4l/2". x 9"v x 2%" set edgewise 3:" apart withalternate coul-seein staggered relationship.

.The cycle length was s minutes, '45% er w'li'len f was occupied in heating and 33% by the'oil admission period, Ithe remaining portionsof thel Ave. set temp passed Ithence into the carburetter top.

cycle were devoted to purges of combustion products and of oil gas.

The oil selected in accordance with this invention,' was a Texas coastal crude oil from the Placedo field, a number 'l oil according to the Bureau of Mines Index to be hereinafter more particularly described, and having a Conradson.

carbon content below 4%. The oil was admitted -to the carburetter top during the run at a rate Average Carburetter top l Carburetter m1ddle. 1 Superheater base 1 Superheater middle 1 Superheater top.

The yield of residual oil gas per gallon of oil was 52.1 cubic feet. The sulfonation residue,

' determined as above described was less than As an example of non-homogeneous cracking the following may be given:

Example 2 A cyclic cracking operation was carried on in a three shell set, connected in series in a similar manner as the shells oi'.a three shell carburetted water gas set. The carburetter and superheater were 2' 9" in internal diameter lined with Carborundum brick and both were devoid of checkerbrick. The carburetter was'apprximately -9 5" long inside and the superheater approximately 23' 6" long inside. I'he surface/volume ratio of the superheater in sq. ft./cu. ft. was approximately 1.6 as compared to 12.4 inthe checkered portion of the superheater in Example 1.

The carburetter and superheater Awere heated during the heating. period by tar burned in the generator, the resultant products passing through the carburetter and superheater.

During the cracking period oil was atomined into the top of the carburetter in the presence of steam which was heated in the generator and The oil was vaporized in the carburetter and the cracking of the oil vapors initiated therein. The mixture of steam, oil vapors and'V some oil gas resulting from the cracking passed from the lcarburetter to the superheater for further cracking of the oil constituents and thence to apparatus for the condensation of hydrocarbons of 4 carbon atoms and higher.

The cycle length was 3 minutes of which 45%` was occupied-in heating, 33% in the oil admission period and the remainder in purges of the apparatusof blast products and of oil gas.

The oil was a. Texas Coastal Crude oil from thePlacedo ield, a No. '7 oil according to, the Bureau of Mines Classification, to be hereinafter more particularly described, and having a Conradson c arboncontent of less than 4%. It was admitted at'a rate of 3.96 gals. per minute, and

steam was admitted with the oil at a rate ofr30.6

lbs. per minute.

'I'he maximum and minimum temperaturesthrough the cycle as observed by shielded thermocouples at spaced intervals through the carburettery and superheater were as follows:

Maximum Minimum Swing Average F. F. F. F. Carburetter top 1, 925 1, 595 350 1, 760 Carburetter mxddle. 1, 895 l, 505 390 i, 700 Superheater base 1, 670 1, 480 190 1, 576 Superheater middle.. 1, 602. 5 l, 497. 5 104 1, 550 Superheater ext 1, 537.5 1, 512. 5 65 1, 550 Ave. set temp 1, 615

The residual oil gas yield was 57 cubic feet per gallon of oil. The sulfonation residue determined A as above described was 0.18. IThe percent; free carbon determined as above described was 1.19. This relationship of sulfonation residue and free carbon is expressed by the point D in Figure 2.

Example '3 An operation similar to that of Example 2 was performed at lower temperatures, with set conditions other than temperature, oil and steam input, cycle length and subdivision remaining the same.

The observed temperatures at the same portions of the set were as follows:

The yield of residual oil gas was" 50.3 cubicft./gal. of oil. 'I'he suifonation residue, determined as above described, was 0.36%.`- The free carbon, determined as above described, was 0.65%.

The relationship between sulfonation residue and free carbon is expressed by the point E in Figure 2. In Example 1 the total yield of the more desir-` able products was not only higher than in Examples 2 and 3 but individual products were cf markedly higher quality.

For example, the total yield of certain very desirable. aromatic resin-forming hydrocarbons, namely. styrene, methyl styrene, vand indene, was 27.7 pounds per gallons of oil in Example 1; 20 pounds per 100 gallons of oil in Example 2; and 19.1 pounds per 100 gallons of oil in Example 3. In Example 1 these materials were in a form in which they could be readily purified for the production of high quality resins, whereas in Examples 2 and 3 considerable contamination of an extremely difilcultly removable naturel was present whichdestroyed the quality of the resins Dro-- duced particularly in the case of styrene.

The total recovery of certainvery desirable non-aromatic resin-forming'hydrocarbons. namely, cyclopentadlene, butadiene, isoprene and piperylene, was 26.4 pounds per 100 gallons of oil in the case of Example 1; 12.9 pounds per 100 gallons of oil in the case of Example 2; and 24.2 pounds per 100 gallons of oil in the case of Example 3. Thus the yield in Example 1 was substantially twice that in Example 2 and somewhat larger lthan that in Example 3. In Examples 2 erably lower concentration in the condensate, there being present a considerably larger quantity of similarly boiling materials. This introduced a problem of separation of a magnitude muchv greater than that in the case of Example 1.

Thus the recovery of indene, methyl styrene, styrene, cyclopentadiene, piperylene, isoprene and butadiene totaled 54.1 pounds per 100 gallons of oil in Example 1 as against 32.9 pounds in Example 2 and 43.3 pounds in Example 3. Furthermore, the products in Example 1 were generally of very much higher quality which is an extremelylimportant consideration when dealing with raw materials to be employed in resin production.

Referring now to the lower boiling saturated aromatics, namely, benzene, toluene and solvent naphtha, the total yield in Example 1 was 105.9 pounds per 100 gallons of oil; 104.6 pounds per 100A gallons of oil in Example 2 and 101.5 pounds per 100 gallons of oil in Example 3.` While the yield in Example l was not particularly greater, these materials were considerably less contaminated. For example, the toluene obtained in Example 1 was readily puried for nitration purposes, whereas the toluene obtained-in Examples 2 and 3 was industrially unsuitable for nitration purposes.

From the foregoing comparisons the outstanding advantages of the invention become readily apparent.

Due at least in part to the different thermal stabilities of the various products, it has not been found that any one set of operating conditions results in maximum production'of all of the several products.

However, within the range of residual oil gas set forth, will be found the peak yields of styrene, the peak yield of toluene, the peak sum of the yields of toluene, solvent naphtha, styrene, methyl styrenes and indene, the peak sum of the yields of styrene, methyl styrenes and indene, the peak sum of the yields of styrene and cyclopent'adiene. Within the preferred range of residual oil gas set forth good yields of benzene, naphthalene, other saturated and unsaturated aromatic compounds contained in dead oil and residual tar, and of butadiene, isoprene, and piperylene may also be secured.

Higher yields of benzene and naphthalene and residual tar may be secured beyond the range of residual oil gas set forth on the high side, but accompanied by reduced yields of styrene, indene and toluene, low yields vof methyl styrene, solvent naphtha and'dead oil,` and very low yields of the dienes particularly butadiene, isoprene and plperylene. The styrene may also be contaminated by relatively large quantities oflphenyl acetylene.

' Higher yields of solvent naphtha, methyl styrene, the dienes, and deadoil may be secured vheyond the range of -residual oil gas set forth on theI low side. 'Ihe solvent naphtha, benzene and toluene in suchcase lare contaminated with rela- Oil classlcation` In the classication of a crude oil in accordance with the Bureau of Mines method disclosed in Bureau of Mines Report of Investigations R. I. 3279, previously referred to, a given petroleum oil is subjected to fractional distillation and two cuts are collected, the first having a boiling range between 250 and 275 C. at atmospheric pressure, and the second having a boiling range between 275 and 300 C. at 40 mm. absolute pressure.

For convenience of identification, the lower boiling fraction is referred to as key fraction 1 and the higher boiling fraction is referred to as key fraction 2.

From the API gravities of these key fractions, the classincation of the original oil is made as follows: y

If the APl. gravity of `key fraction 1 is 33 or 'below 33, the fraction is classined as naplithenic; if it is between 33 and 40 tne fraction is ciassined as intermediate; and if it is 40 or above 40 the fraction is classified as paraiiinic.

If the API gravity of key fraction 2 is 20 or belowl 20, the fraction is classined as naphthenic; if it is between 20 and 30 the fraction is classined as intermediate; and if it is 30 or above 30 the fraction is classied as c.

As a result of the foregoing classifications of the key fractions, the `original oil is given one of seven classiiications as follows! 4 If both key fractions are parafiinic, the original oil falls in class 1. If key fraction 1 is paramnic and key fraction 2 is intermediate, the original oil falls in class 2.

If key fraction'l is intermediate and key fraction `2 is paraiilnic the original oil falls in class 3. 1 If both key fractions are intermediate, the original oil falls in class 4. 1

If key fraction l is intermediate and key fraction 2 is naphthenic the original oil falls in class 5.

Ifvkey fraction l is naphthenic and key fraction 2 is intermediate the original oil falls in class.

If both key fractions are na'phthenic, the original oil falls in class 7.

Based upon the foregoing classification in accordance with the present invention, we employ oils falling within the classes 5 to 7 inclusive, or

desired cuts from such oils with class 'Z oils orV a desired cut or cuts therefrom preferred, provided,

. however, that in the Acase of any oil selected whether a crude or a cut, the Conradson carbon of the oil does not exceed approximately 7% and preferably does not exceed approximately 4% The test for Conradson carbon has been standardized under the American Society of Testing Materials Designation D189-36 and Conradson carbon as used herein is that Conradson carbon .determined under such procedure.

percentage of Conradson carbonis an indirect vmeasure of the tendency of anoil to formcarbon and'hydrog'en on pyrolysis instead of the I valuable hydrocarbons desired.

Referring now more particularly to the characf ter of the oil pyrolyzed, as previously stated, this .evaluation factor which we term evaluation factor B. D. D." and which is a function of the average boiling point, the density and the mean dispersian of oil.y

'increase. F. and its occurrence indicates undesirable liquid Speciiically, this evaluationvfactor is a product function of two factors-factor I and factor II.

Average boiling point vlI-114) g 20/4Xl0270.7

Evaluation lector B. D. Ill-Factor IX Factor IIXl2= Average boiling point 'un-160) 1 d ---VX10, 65 vos x10-1 The Average boiling point employed is deter- Factor I=156492 (loglog FactorII=l004 (Sin arc Tan [1004(sm are' 'ran mined by making a modied straight run Engler distillation of the oil and observing the temperatures at which 15%, 30%, 50%, 70% and 85% by4 that for the thermometer described there is sub-- stituted anl A. S. T. M. general purpose thermometer (20760 F.) 3 inches immersion.

'7 oils inclusive, andalso yields of such products and product groups obtained in the pyrolysis of cuts of such oils.

When (Hr-cx 104) is less than 65 it is assumed to be'65, so that the maximum value of factor 1I is 98.0 and'so that' negative values do not occur. Evaluation factor B. D. D. may be calculated directly from the formulaor if desired it may bev calculated by constructing nomograms (not shown) expressing the equations of factors I The procedure described is modified so that the determinations are made on a volume basis and temperatures are read at which 15%, 30%, 50%, 70% and 85% of the material is distilled over. Separation of cuts, determinations of their specific gravity, and coking determinations are unnecessary. v

The preheating period should be 'not less than 10 minutes nor more than 20 minutes. higher boiling oilsfhaving the longer preheating.

The rate of distillation is carefully adjusted,

vby the needle valve on the burner,to 4 cc. per

minute and this rate is maintained unless a slight drop in temperature accompaniesa rate (This will not usually occur below 500 phase cracking.) In this event, the heating is increased so that the thermometer is returned l to its previous reading regardless of the rate. If

the rate then decreases with constant increase in temperature, it is permitted to do so until a rate or ice/min. is again reached.' If the rate does not so decrease, the distillation isccntinued Iin such manner that the temperature constantly rises.

s 'the iive temperature readings is employed as the average boiling point.

The density d /4'is determined by employing tics and the results ofy petroleum oilpyrolysis.

A large number of crude oils ranging from Bureau of Mines class 1 oils to Bureau of Mines class 7 -oils inclusive and cuts from certain of the crudes on examination gave evaluation fac- The formulae for evalution B. D. D. were empiri'cally derived from petroleum oil characteris- They are not intended to apply to the pyroiysis of individual pure hydrocarbons. However, a fair aromatic compounds is obtained even when the petroleum'oil has'had added to its quantities of benzene, for example 25% by volume.

In Aaccordance with the present invention, there is selected for pyrolysis hereunder, crude petroleum oils or cuts from such oils having evaluation factors B. D. D. above 68 and preferably above 74.

If a given set is operated to crack (1l a petroleum oil selected as herein set forth. (2) relatively homogeneously and (3) relatively uniformly as herein denned. and (4) if the production of residual oil gas is held between the approximate limits above given, a substantially larger quantity of alkylated and alkenated aro' matic hydrocarbons. including a substantially larger quantity of aromatic resin-forming hydrobefore .stated the Aarithmetical average of a Sprengel pycnometer. It is denned as the ratio oitheweightinairoi'caofoilatm' C.tothe.

Weisht in air or 5cc. of water at .4* C..

Themean dispersionHroisdennedasthe diii'erence between the refractive index .of the oil as determined with the F spectral line and the -refmuve index of the ou s.; determines with .the C spectral line, employing solvent naphtha and toluene and aromatic resin formera such as styrene, methyl styrene and indene. Y

It has the advantage or -a'pplvi'ntto cuts from crude petroleum ,oils as well as the exudes, except-such cuts as residuurns` too darkto permit B. D. D.v isa convenient f carbons, together with substantialquantities. of other unsaturated resin-forming hydrocarbons and of saturated aromatic hydrocarbons are produced, and witha substantial reduction of paramnes and non-aromatic oleilnes boiling with the ranges of the saturated aromatic hydrocarbons.

In discussing the selection oi" petroleum oilfor pyrolysis, it has been stated that a crude vv'oil having the, desired characteristics or a decondensation may be accomplished by any suit able means.

- 4Generally therelare four tools'anaiil-v 'able for this purpose, namely. refrigeration, compression, absorption, such as in aescrub'bing oil, and adsorption, such as on activated carbon. These may be. used singly4 orinlany desired combination.

Means vfor recovering valuable hydrocarbons thcideterminationof themean dispersion, and from the gas produced is illustrated in Figures aessma 3 and 4 which figures when arranged end to end comprise a continuous iiow sheet.

At the extreme left of Figure 3 is shown line i9 and wash box d together with gas outlet 20a and valve 2l of Figure 1.

As illustrated, outlet 20ar leads to a multi-pass condenser ll which may be of any suitable design. Condenser il is shown with a gas outlet l2 which leads to a gas cleaner 43 of any suitable design for the removal of entrained tar. Outlet @t from gas cleaner d3 leads through drip pot 4E of any suitable design and into relief holder d5 through vertical pipe lil.

Wash box d is provided with a water supply d and tar overflow i9 which leads to tar seal p ot 5&4 to which as illustrated is connected a vapor outlet 5l leading to a condenser 52 for the recovery of any vaporized material.

Tar ows from seal pot 50 through outlet 53 and may be drawn of separately through line 5t or may be combined through line 55 with the tar from the nrst vertical pass of condenser dl which latter tar drains through line 56 into seal pot 5l with which line 55 connects. Seal pot 5l is provided with a vapor outlet 58 which may lead to a condenser (not shown) and with a tar outn let 5S.

Additional seal pots 6|, 62, G3, $5, 65 and S6 have been illustrated, each connected to a separate vertical pass of condenser il for the withdrawal of tar. Each. ofv the seal pots -may be constructed similarly to seal pot 5l including a vapor outlet with a condenser (not shown) and a tar outlet.

Gas cleaner t3 is also shown with a tar outlet E8 leading to seal pot S9 which also may be similar to seal pot 5l.

'The particular arrangement of seal pots 5d, 5l, 6l, 62, 63, tl, G5, 65 and 69, each of which is provided with a separate tar outlet makes it possible to separately process the tar condensedat various points, if desired, or to combine the separate bodies of tar in any desired manner prior to processing. For example, the tar flowing from seal pots 50, 5l and 6l might be combined to form heavy tar, and the tar ilowing from seal pots 62, 63, td, B5, and 66 might be combined to form light tar.

It will be understood, of course, that any other suitable construction or arrangement or method of Icollecting tar might be substituted.

As illustrated, the condensate collected in drip pot t5 is drawn oil' through outlet ll and since it is usually non-tarry in nature, if desired, it

processed, as desired.

as provided with condensate drains lill,

Purifier boxes 79 and 80 are illustrated with drip pots Bl and 82 respectively for the co1lec-n tion and removal of condensate.

Outlet 8d from the purifier system 'i3 leads through gas meter 85 and past thermocouple junction 86 which is connected to pyrometer tl for measuring the gas temperature. Gas pressure gauge 88 is also provided.

The purpose of meter 85, pyrometer 8l and pressure gauge 88 is to furnish data for calcue lating the volume of gas flowing through outlet B v If residual oil gas is to Abe calculated from this data a sample of the gas for analysis should be taken at this point.

Since condensation may occur in outlet 8d, a drip pot 89 is illustrated in this outlet. It is to be understood that a drip pot or drip pots may be placedat any other point or points in the system for the collection and removal of condensate.

As illustrated, outlet t@ leads to compressor Si driven by a prime mover 92, thev gas passing through compressor 9 l; then through after-cooler @3,'through a second compressor 9d, after-cooler 95, a third compressor 96, after-cooler @7, and through line 93 to a scrubbing tower 99. Each o f Vthe after-coolers- 93, 95 and 97 is illustrated M32, and H93 respectively which as illustrated are connected to a common line i0@ to be referred to again hereinafter. The after-coolers may be of any suitable design and operation.

Each of the compressors @t and 96 is also illustrated as driven by a prime mover 92.

Any other means may be provided for raisingsate.

Hydrocarbons also may condense within the relief holder d6 and if so are skimmed oiivof the top of the water through drain l2. This condensate is usually non-tarry in nature and is' of the nature of light oil. Therefore, if desired, it may be combined, for example, with similar or lighter condensate and processed therewith.

Relief holder d6 is illustrated with the conventional water inlet 13 for replacing water losses from the tank thereof.

Relief holder 4E is shown with gasvoutlet 15 which leads through drip pot 16 and line l1 to the gasy purifier system illustrated1 generally at 78 and more specifically as containing iron oxide boxes 19 and 80, althoughl it is to be understood that any suitable gas purier system-may be substituted. The connections to the puriner boxes 19 and 80 are conventional and will, there-f" fore, not be more particularly descrlbed.

Generally speaking, the pressure in the system from wash box d to and through outlet 8d is conveniently slightly above atmospheric. The pressure in outlet 98 may be as desired, for example, in the particular system illustrated conveniently of the order of from 200 to 225 lbs. per

-square inch absolute.

The temperature of the gas in outlet 8f3 may be conveniently maintained at any desired level such as between and 100 F. Reference is made to copending application, Serial No. 301,330, led October 26, 1939, now Patent 2,379,518, dated July 3, 1945. The temperature of the gas in outlet 98 may also be as desired, for example, conveniently of the order of from 85 to 100 F.

As illustrated outlet 9B is connected to the bottom of scrubber 99, the gas passing up through scrubber 99 countercurrently to a liquid gasscrubbing medium of considerably lower vapor pressure such as a scrubbing oil. The scrubbing medium enters scrubber 99 through line MD5 which leads from the bottom of stripping tower IM throughcooler I06-to the top of scrubber 99. The proportion of scrubbing oil to gas and the temperature of the scrubbing oil is conveniently sharp separation between hydrocarbons of 3 and 4 carbon atoms for the purpose of calculating "residual oil gas" using as a sample this eilluent ses is not an indispensible essential.

For

The eiliuent gas is led through gas meter |00,

past thermocouple junction |09 leading to pyrometer IIO, and past pressure gauge III. A purpose of meter |08, pyrometer III) and pressure gauge III is to determine the volume of eiiiuent gas for purposes of calculating residual o il gas,

provided residual oil gas is calculated'irom the analysis of gas sampled at this point.

It will of course be understood that even though a substantial portion of hydrocarbons of less than 4 carbon atoms were condensed it would, nevertheless, be possible to calculate resdual oil gas as herein defined1 by adding to the residual oil gas as determined from the sample a volume to compensate for such condensation.

Returning to scrubber 95, scrubbing medium containing condensate is withdrawn through line II3, through heater |25, and fed to` the top of stripper H4 in which condensate scrubbed from the gas in scrubber 99 is stripped from the scrubbing medium such as with the aid of live superheated steam introduced through line II2. The stripped material is taken overhead through line I I5 to and through condenser H6 which leads to decanter- II'I and the scrubbing medium is returned through line |05 and cooler |06 to scrubber 99, any makeup being added as required.

Decanter II'I is conveniently provided for the separation of condensed water and of any gas remaining uncondensed after passing through condenser IIS. Uncondensed gas is led through line II8 back to line 84 and is thus recycled through the compressors.

Line |04 conveniently leads to decanter II'I in which condensate from after-coolers 93,. 95 and 91 is combined with condensate from condenser IIS.

Any Water collecting in decanter I I1 is drained of! through line I I9, and hydrocarbon condensate is drained off through line |20'into fractionating tower I2I. A separation is made between higher and lower boiling hydrocarbon components in tower |2I, for example, between hydrocarbons of 6 carbon atoms and higher which are taken off in the liquid phase at the bottom through line |22, and hydrocarbons. oi less than 6 carbon atoms which are taken off in the vapor phase through line |23. The latter are condensed, a part returned to tower I2I as redux, and the rest lead to fractionating tower |24 in which a separation is made between hydrocarbons of 5 carbon atoms and higher which are taken oir in the liquid Vphase through line |26, and hydrocarbons of less than 5 carbon atoms which are taken oi in the vapor phase through line |21. The latter are condensed, a part returned to tower |24 as reux, and the rest lead to suitable apparatus for the recovery of hydrocarbons with 4 carbon atoms (not shown).

The unsaturated hydrocarbons of 5 carbon atoms, namely, isoprene, piperylene, and cyclopentadieue may be separated from each other. by any available means such as by the processes described and claimed in Patent 2,211,038 granted `August 13, 1940, to Alger L. Ward and in copending application Serial Number 342,910, filed June r28, i940, by Alger L. Ward.

-vThe unsaturated hydrocarbons of 4 carbon atoms, namely, butadiene and the butylenes may also be separated from each other by any available means such as by the processes described in the literature including granted patents.

The tarls processed for the recovery of light oil, dead oil and residual tar therefrom, either tions according to the method of collection. Since v steam is usually used in the pyrolysis of the oil,

and since the resulting gaspassesthroughihe wash box 4 which contains water, the tar is usually collected in the form of an emulsion.

This emulsion is usually broken during the treatment for the recovery of light oil, dead oil and residual tar.

Any means may be employed for the recovery oflight oil, dead oil and residual tar from the original tar, such as the conventional tar dehydration procedure using batch distillation followed by fractionation of the distillate into light oil and dead oil. However, it is preferred to use more refined processes such as the process described in copending application Serial Number 342,735, filed June 27, 1940, by Edwin L. Hall and Howard R. Batchelder, now Patent 2,366,899 dated January 9, 1945, and Serial Number 353,034, iiled August 17, 1940, by Howard R. Batchelder.

The condensate collected from the various drip pots and from the holder 46 is usually not in the form of an emulsion, and the various valuable hydrocarbons are recovered thererom'usually by distillation. Ii desired, the condensate drained from the various drip pots and from holder 45 may be combined with the condensate fed to tower I2 On the other hand, this material may be combined with the light oil separated from the original tar and processed therewith.

ALight oil recovered from the tar, and Ithe condensate from the drip pots, and the holder, and the heavier hydrocarbon' material separated in tower I2| are sources for benzene, alkylated benzenes such as toluene and the xylenes. for resin forming unsaturated hydrocarbons such as styrene, the methyl styrenes, dicyclopentadiene and indene as well as other valuable hydrocarbon material. separations between 40ithese various hydrocarbons may be made by in a single combined body or in any selected porresorting toI fractional distillation or other means to obtain relatively pure products or fractions in which the individual hydrocarbons specifically mentioned lare concentrated.

Thus styrene may be separated in relatively pure form by special processing or by distillation i into concentrated fractions which are preferably of at least approximately 30% concentration, since below this concentration serious contamination is present. Concentrations as high as approximately 60% or higher are obtainable bydistillation and are especially preferred.

With indene the lower concentration is preferably atleast approximately 50% and the higher n concentration is at least approximately 80%.

With the methyl styrenesas a group the respective percentages-are approximately the same as with styrene, and with dicyclopentadiene the respective percentages are approximately the same as with indene.

Y In addition to high quality resin-forming unsaturated hydrocarbons, the light oil produced by the process described and claimed herein yields high quality benzene, toluene and solvent naphtha especially within the preferred range of residual oil gas" production.

Butadlene is concentrated in a fraction pref- 'erably of at least approximately 35% and especially of at least 50%.

The Cs diolenes, namely, isoprene, piperylene and cyclopentadiene, some of the latter, in the form of its dimer dicyclopentadiene, which may be in the separation, are preferably separated by fractional distillation or otherwise, in a yfraction of at least 30% concentration.

Benzene, a substantial quantity of toluene, some styrene and xylenes are recovered from the material removed through line |22. 'I'here is also through line |26.

A substantial quantity of C4 hydrocarbons some C3 and C2 hydrocarbons and a small quantity of C5 and C1 hydrocarbons are recovered from the material withdrawn through line |21. The quantity of hydrocarbons present of less than 4 carbon atoms in this material should be considered in the calculation of residual oil gas.

The dead oil depending upon the method of separation from the original tar may contain an unusually high percentage of' very valuable aromatic resin-forming material which is extremely unusual. 'I'he dead oil also contains a large number of saturated 'hydrocarbons for example naphthalene, substituted naphthalene, an-

.thracene, etc.

A high grade of residual tar is obtained, useful for the various purposes to which material of th'is type is put. n

It will be understood, however, that the particular description with respect to the removal of valuable hydrocarbons from the gas and their separation is for the purposes of illustration and that any other suitablesystem for this purpose might be substituted.

It is to be understood that if desired other materials may be added to the oil pyrolyzing environment in addition to the selected petroleum oil. For example, othenhydrocarbon materials 'I such as benzene, toluene, xylene and solvent naphtha may be added.

As an illustration the addition of benzene to the oil cracking environment as described and claimed in copending application Serial Number 220,649, led July 22, 1938, by' Newcomb K.

Any suitable quantity of such material may be added as for example, up to 25% to 50% of benzene by volume ol.' oil pyrolyzed. l v

When making any such aromatic hydrocarbon additions which preferably are restricted to materials which for the most part boil below 200 C., ,residual oil gas `for convenience may be calculated as previously described, namely on the basis of petroleum oil pyrolyzed, with no deduc- Chaney (now Patent Number 2,226,531, dated December 31, 1940), is particularly beneficial when relatively large yields of certain resinforming unsaturated hydrocarbons such as 'styrene is desired.

' Materials of this character may be added to the oil cracking environment at any desired point such as at the point of introduction of the petroleum oil, or at any other desired point or tion being made lfor any material of less than vfour carbon atoms which might be derived from the additive. However, to the top of the range of residual .oil gas is added 1 cubic foot of gas for each 3% with from 45 to 65 cubic -feet of residual oil .A

gas preferred. 1

According to another method of calculation designed to bring these operations within the broad range of residual oil gas employed as limits vwhen no additive is employed, namely 40 to 65 cubic feet per gallon of petroleum oil pyrolyzed no subtraction is made for the presence of aromatic hydrocarbon additive when the residual oil gas calculated as herein described is between 40 and 65 cubic feet per gallon of petroleum oil pyrolyzed, but a-substraction up to 10 cubic feet is made from the' residual oil gas to bring thel residual oil gas within the limits of from 40 to 65 cubic feet if on calculation as herein set forth the residual oil gas" exceeds 65 cubic feet.

, While the invention has been more particularly described in connection with more or less conventional apparatus, it is to be understood that this is by way of illustration and that in its .broad phases the invention may be employed with any suitable type of apparatus.

Additionally, whileI the invention has been described primarily in connection with the decomposition of va selected petroleum oil by pyrolysis, it is conceivable that pyrolysis may be supplemented by other means for decomposing the oil of which catalysis is an example. In iact even in conventional gas making processes catalysis may `unavoidably play a part in view of the heterogeneous character of the reactions involved and the possibility of many different materials points such as directly into the zone ci major y cracking.

.The 'additive need not be a pure substance but may comprise for example benzol, toluol, xylol,

solvent naphtha or any other portion of light oil or even overall light oil itself.-

However particularly advantageous results are obtained when benzene itself or a fraction containing a substantial quantity of benzene such as a fraction preponderantly of benzene is used.

In view of equilibrium considerations there is a particular advantage in separating these products from the condensate produced and recycling them to the oil pyrolyzing environment in which they were produced. Thus for example, benzol may be separated from the condensate and recycled back to the set in which thef benzol was originally produced.

being present. IThus, a combination of temperature and catalyst is within the purview of the invention in its broadest aspects.

Therefore, changes, omissions, additions, substitutions, and/ormodications might be made.

within the scope of the claims without departing from the spirit of the invention. We claim:

1. A process vfor the production im relatively` high proportion and in good quality 0f resinforming unsaturated aromatic hydrocarbons including resin-forming unsaturated aromatic hydrocarbons boiling above 200 C, andl of other aromatic hydrocarbons in good quality, which comprises pyrolyzing .a petroleum oil selected v ofthe original oilpyrolyzed. mw ,ALAwproeess for the production sity of cracking such that the volume of residual oil gas produced per .gallon of petroleum oil pyrolyzed falls within the range of from 40 to 65 cubic feet taken as if measured at a pressure of 760 mm. and at a temperature of 60 F., and under conditions such that the relationship between the suli'onation residue and the free carbon obtained is within the sulfonation residue-free carbon relationships lying to the left of and below the curve deiined by the equation in which X and Y are respectively rectangular coordinates oi' tree carbon expressed in percent by weight of the original oil pyrolyzed and of sulfonation residue expressed in percent by volume of the original oll pyrolyzed.

2. A process for the production in relatively high proportion and in .good quality o! Aresin forming unsaturated aromatic hydrocarbons including resin-forming unsaturated aromatic hydrocarbons boiling above 200 C. and of other aromatic hydrocarbons in good quality, which comprises pyrolyzing a crude petroleum oil of below 4% in Conradson carbon and falling within the classication 'l as determined by the Bureau of Mines Indexl and conducting said pyrolysis in vapor phase in the presence of a substantial proportion of steam and with an intensity of cracking and the free carbon obtained is within the sulionation residue-free carbon relationships lying to the left of and below the curve dened by the equation' X33(Y-0.03)=0.05 in which X and Y are respectively rectangular coordinates of free carbon expressed in percent by weight ot the orig-l inal oil pyrolyzed and of sulfonation residue expressed in percent by volume oi' the original oil 3. A process for the production in relatively high proportion and in good quality of resinforming unsaturated aromatic hydrocarbons in-` cluding resin-forming unsaturated aromatic hydrocarbons boiling above 200 C. and of other aromatic hydrocarbons in good quality which comprises pyrolyzing a fraction separated from a petroleum oil of less than 4% in Conradsoncarbon and falling within the classification 'I as determined by the Bureau of Mines Index, and conducing said pyrolysis in vapor phase in the lpresence of a substantial proportion of steam and with an intensity of cracking such that the volume of residual oil gas produced per gallon of petroleum oil pyrolyzed falls within the range ot from 40 to 65 cubic feet taken as if measured at a pressure of 760 mm. and at a temperature of 60 F., and under conditions such that the relationship between the sulionation residue and the free carbon obtained is' within the sulfonation residue-free carbon relationships lying to the left of .and belowthe curve deiined by the equation X=(Y0.03)=0.05 in which X and Y are respectively rectangular coordinates of free carbon expressed in percent by weight` of the original oilpyrolyzed and of sul- Ionation residue expressed. in percent by .volume in relatively high proportion and in` good'quality of resin- `forming unsaturated aromatic hydrocarbons including resin-forming unsaturated aromatic hyf drocarbons boiling above 200 C. and ot other aromatic hydrocarbons in good quality which 'comprises pyrolyzing a petroleum oil of below 7% in Conradson carbon and falling within the classiiication of from 5 to 7 inclusive as determined by the Bureau oi Mines Index,`and conducting said pyrolysis in vapor phase in the presence of a substantial proportion o! steam and at a total pressure near atmospheric and with an intensity of cracking such that the volume of residual oil gas produced' per gallon of petroleum oil pyrolyzed falls within the range of from 40 to 65 cubic reet taken as if measured at a pressure of 760 mm. and at a temperature 'of 60 F., and under conditions such that the relationship between the sulfonation residue and the free carbon obtained is within. the sulfonation residue-free carbon relationships lying to the left of and below the curve defined by the equation X2"(Y-0.03) =0.05 in which X and Y are respectively rectangular coordinates of free carbon expressed in percent by weight of the original oil pyrolyzed and of sulfonation residue expressed' in percent by volume of the original oil pyrolyzed. l

5. A process for the production in relatively high proportion and in good quality of resin-v forming unsaturated aromatic hydrocarbons including resin-forming unsaturated aromatic hydrocarbons boiling above 200' C.`and oi other aromatic hydrocarbons in good quality which comprises pyrolyzing in vapor phase a petroleum oil having an average boiling point-density-mean dispersion evaluation factor above 68 as determined by the formula: t

Evaluation iaotor= presence of a substantial proportion ofdiluent gas under conditions such that the volume of residual oil gas produced per gallon of petroleum oil pyrolyzed falls withinthe range of from 40 to 65 cubic feet taken as if measured at a pressure of 760 mm. and at a temperature of 60 F., and such that the relationship between the sulfonation residue and the free carbon obtained is within the sulfonation residue-free carbon relationships lying to the left of and below the curve defined by the equation Knuf-0.03) =0.05 in which X and Y are respectively rectangular coordinates oi' free carbon expressed in percent by weight ofthe original oil pyrolyzed and of sulfonatlon residue expressed in percent by volume of the original oil pyrolyzed.

6. A process for the production in relatively high proportionY` and in good quality of' resinforming unsaturated aromatic hydrocarbons including resin-forming unsaturated aromatic hydrocarbons boiling above 200 C. and of other aromatic hydrocarbons in good quality which comprises pyrolyzing in vapor phase a pertoleum oil Y having an average boiling point-density-mean assav'za conducted under conditions such that the volume of residual oil gas produced per gallon of petroleum oil pyrolyzed falls within the range of from 40 to 65 cubic feet taken as if measuredat a pressure of '760 mm. and at a temperature of 60 F., and such that the relationship between the sulfonation residue and the free carbon obtained is within the sulfonation residue-free carbon relationshim lying to the left of and below the curve defined by the equation X13( Y-0.03) :0.03 in which X and Y are respectively rectangular coordinates of free carbon-expressed in percent by weight of the original oil pyrolyzed and of sulfonation-residue expressed in percent by volume of the original oil pyrolyzed.

7. A process for the production in relatively high' proportion and in good quality of `resin-forming unsaturated aromatic hydrocarbons including resin-forming unsaturated aromatic hydrocarbons boiling above 200 C. and of other aromatic hydrocarbons in good quality which comprises pyrolyzing in vapor phase a petroleum oil having an average boiling point-density-mean dispersion evaluation factor above 74 as determined by the a formula:

Evaluation factor= Average boiling point F.-ll4 [15.6492 (mg d maxim-10.7

[i004 (sin. are TanW-m 966] 1o2 in which d 2074 is th'e density of the oil at 20 C. as compared with water at 4' C. and HF-c is th'e mean dispersion of the oil employing the F and C spectral lines, conducting said pyrolysis in the y presence of a `substantial proportion of steam while restricting any blue water gas present to less than approximately cubic feet per gallon of petroleum oil pyrolyzed, said cubic feet of blue water gas taken as if measured at a pressure of 760 mm. and at a temperature of 60 F., and also conducting said pyrolysis under conditions such that the volume of residual oil gas produced per gallon of petroleum oil pyrolyzed falls within the range of from to 65 cubic feet taken as if measured at a pressure of 760 mm. and at a temperature of F., and such that th'e relationship between the atively high proportion and in good quality of" resin-forming unsaturated aromatic hydrocarbons including resin-forming unsaturated aromatic hydrocarbons boiling above 200 C. and of i other aromatic hydrocarbons in good quality in which in one portion of the cycle heat is stored in a gas-making path bythe passage of hotblast gas portion of the cycle the stored h'eat is employed to pyrolyze petroleum oil passed through said gasmaking path and over said heated surface, the steps of pyrolyzing in said gas-making path a petroleum .oilhaving an average boiling pointdensity-mean dispersion evaluation factor above 68 as determined by the formula:

Evaluation factor= in which d 20/4 is the density of th'e oil at 20 C. as compared with water at 4 C. and Hs'c is the mean dispersion of the oil employing the F and C- spectral lines, and conducting said pyrolysis under conditions such that the volume of residual oil gas produced per gallon of petroleum oil pyrolyzed falls within the range of from 40 to 65 cubic feet taken as if measured at a pressure of 760 mm. and at a temperature of 60 F., and such that the relationship between the sulfonation residue and the free carbon obtained vis .within the sulfona .tion residue-free carbon vrelationships lying to the left of and below the curve defined by the equation X2-3(Y0.03)=0.05 in `which X and Y are respectively rectangular coordinates of free carbon expressed in percent by weight of th'e original oil pyrolyzed and of sulf'onation residue expressed in percentby volume of the original oil pyrolyzed. l

9. In a cyclic Process for the manufacture in relatively high,proportion and in good quality of resin-forming unsaturated aromatic -hydrocarb ons including resin-forming unsaturated` aromatic hydrocarbons boiling above 200 C, and of other aromatic hydrocarbons in good quality in which in one portion of the cycle heat is stored in a gas-making path by the passage of h'ot blast gas vtherethrough/in contact with thc surface of heat storage vmaterial arranged therein and in another portion of the cycle the stored heat is employed in the vaporphase pyrolysis of petroleum oil passed through' said gas-making path, the steps of pyrolyzing in said gas-making path a petroleum oil having an average boiling point-density-mean dispersion evaluation factor above 68 as deter-l mined by thel formula:

' Evaluation iector= verage boiling point Uit-114)] [-492Q0g10g d maxim-70.7 l

in which d 2li/41s the density of the on at 20C. as compared with water at 4 C. and Hr-o is the mean dispersion of the oil employing the F and C spectral lines, conducting said pyrolysisin vthe presence lof a substantial proportion of th'e steam while restricting the presence of any blue water of residual oil gas produced per gallon of petr'o-. leum oil pyrolyzed falls within the rang of froml 40 to 65 cubic feet taken as if'measured at a pres-4A sure of 760 mm. and at a temperature of 60 F.,

and such that the relationship between the sulfonation residue and the free carbon obtained is therethrough in contact with' the surface of heatl storage material arranged therein and in another tionships lying to the left of and below the curve defined by the equation X2"(Y0.03)=0.05 in which X and Y are respectively rectangular coordinates o l free carbon expressed in percent by 6 assegni within the sulfonation'res'idue-free carbon relasaid 'gas-making path a petroleum oil having an average boiling point-denslty-mean dispersion evaluation factor above 74 as determined by the formula: A

Evaluation factor- Average boiling point F.-114)] [1M-492 (Mm d asfixia-70.1

of resin-forming unsaturated aromatic hydrocarbons including resin-forming unsaturated arof matic hydrocarbons boiling above 200 C. and of other aromatic hydrocarbons in good quality in which in one portion of the cycle heat is stored in a gas-making path by thepassage otburning blast gas therethrough in contact with the surface of heat storage material of silicon carbide arranged therein. and in another portion of the cycle the stored heat is employed in the vapor phase pyrolysis of petroleum oil passed through v said gas-making path and over said heated surface, the steps of pyrolyzing in said gas-making path a petroleum oil having an average-boiling point-density-means dispersion evaluation factor above 68 as determined by the formula:

valuation factor:

. in which d /4 is the density of the oil at 20 C.

as compared with water at 4 C. and Hr-c is the mean dispersion of the oil employing the F and C spectral lines, conducting said pyrolysis at 'a total vpressure near atmospheric in the presence of at least 2 parts of steam to 3 parts of oil pyrolyzed by weight while restricting the presence of any blue water-gas to less than cubic feet per gallon of oil pyrolyzed, said cubic feet of blue water gas taken'as if measured at a pressure of 760 mm. and at a temperature of 60 FL, and also conducting said pyrolysis under conditions such that the volume of residual oil gas produced per gallon of petroleum oil pyrolyzed falls within the range of from 40 to 65 cubic feet taken as if measured at a pressure of 760 mm. and at atemperature of F., and such that the relationship between the sulfonation residue and the free carbon obtained is within the sulfonation residue-free carbon relationships lying to the left ol?V and below the curve dened by the r`equation X23( Y'0.03)=0.08 in which X and Y are respectively rectangular coordinates of free carbon expressed in percentby weight of the original oil vpyrolyzed and of sulionation lresidue expressed in percent by volume of the original oil pyrolyzed. i

l1. In a cyclic process for the manuracturein relatively high proportion and in good quality of resin-forming unsaturated aromatic hydrocarbons including resin-forming unsaturated aro-4 matic hydrocarbons boiling 'above `200 C. and'ot other aromatic hydrocarbons in good quality in which in one portion of the cycle heat is stored in a gas-making path by the passage of hot blast p gastherethroughin contact with the surface o! `heat storage material arranged 'therein o! considerably higher heat conductivity than ilreclay -brick and in another portion of the cycle the stored heat ls 'employed in the vapor phase pyrol-V ysis of petroleum oil passed through "saldgasin which d 20/4 is the density of the oil at 20 C. as compared with water at 4 C. and I-Ir-o is the mean dispersion ofv the oil employing the F and C spectral lines, conducting said pyrolysis in the presence oi at least 2 parts of steam to 3 parts by weight ofpetroleum oil pyrolyzed while restricting the presence of any blue water gas to less than 20 cubic feet per gallon of oil pyrolyzed,

20 said cubic feet o! blue water gas taken as if measured at a pressure o1' 760 mm. and at a temperature of 60 F., and also conducting said pyrolysis under conditions such that the volume of residual oil gas produced per gallon of petroleum 2'5 oil pyrolyzed falls within the range of from 45 to cubic feet taken as if measured at a pressure of 760 mm. and at a temperature of 60 F., and such that the relationship between the sulonation residue and the free carbon obtained is within the sulfonatin residue-free carbon rela- .Itionships lying to the left of and below the curve dened by the equation X2-3(Y-0.03) :0.01 in which X and Y are respectively rectangular coordinates of free carbon expressed in percent by 35 weight of the original oil pyrolyzed .and of sulonation residue expressed in percent by volume of the original oil pyrolyzed.

12. In a cyclic process for the manufacture in relatively high proportion and in good lquality of yso resin-forming unsaturated aromatic hydrocarbons inclu resin-forrning unsaturated aromatic hydrocarbons boiling above 200 C. and of other aromatic hydrocarbons in good quality in vwhich in one portion of the cycle heat is stored i5 in a gas-making path by the passage of hotfblast gas therethrough in contact with the surface of heat storage materialarranged therein of considerably higher heat conductivity than that of re clay brick and in another portion of the 50 cycle the stored heat is 'employed in the vapor phase ,pyrolysis of petroleum oil passed through w density-mean dispersion evaluation factor above 'o. as compared with water at 4 C. and Hiv-c is the 68 as determined by the formula:

y Evaluation fwm- Average boiling int F.l60) [1004(8111. are rm. nl cxwh -cos x10-I m which d :zo/4 is the density of the on at 20C.

mean dispersion of the oil employing the F and C v spectrallines, conducting said pyrolysism'in th presence of at least 2 parts ofsteam -to 3 parts by weight of'petroleum oil pyrolyzed while remaking path, the steps comprising pyrolyzing in stricting the presence of any blue water gas to less than 30 cubic feet per gallon of oil pyrolyzed, said cubic i'eet of blue water gas' taken as if measured at a pressure of '160 mm. and at a temperature of 60". F., and'also conducting said byrolysis under conditions such that the volume oi residual oil gas produced per gallon of petroleum oil pyrolysed falls within the range of from 40 to 65 cubic teet ,taken as i! measured at a pressure of 760 mm.

sandiat a temperature of 60 F., and such that the relationship between the sulionation residue and the free 'carbon obtained is within the sulionation residue-free carbon relationships lying to the left of and below the curve dened by the equation Knuf-0.03) =0.03 in which X and Y are respectively rectangular coordinates of tree carbon expressed in percent rby weightfoi the original oilpyrolyzed and of sulionation residue expressed in percent by volume of the orisinal oil pyrolyzed.

13. In a cyclic process tor the manufacture in relatively high'propor-tion and in good quality of resin-forming unsaturated aromatic hydrocarbons including resin-forming unsaturated aromatic hydrocarbons boiling above 200 C. and of other artic hydrocarbons in good quality in which in one portion of the cycle heat is stored e of hot blast gas therethrough in contact with the surface of heat storage terial of silicon carbide `arranged therein and in another portion of the'cycle the 'stored heat is employed in .the vapor phase pyrolysis ci petroleum oil passed through said gasmahing path over said heatedsuriace, the

.petroleum oil having an average' boiling pointdensity-mean dispersion evaluation factor above 74 as'deteed by the formula:

Evaluation lector-1- Average boiling p omt F.11'4 im 920mm d maxim-10.7 :E

m which d /4 is the density of the on at zur c. as compared with water at 4 C; and Hr-o is the C spectral lines, conducting said pyrolysis in the presence of a substantial proportion oi' steam lunder conditions such that the volume'oi residual oil gas produced per gallon of petroleum oil pymean dispersion of the oil employing the F and mean dispersion evaluation factor above 68 as determined by the formula:

Average boiling p oint F.-1i4) [159 92 (Mm a coaxial-70.1

[1004(8111. are TMW) -9o]x1o 1 1n which a zo, 4 is the density of the ou at 20 c. 'as compared with water at 4 .C. and Hr-o is the mean dispersion of the oil employing the F and C spectral lines, conducting said pyrolysis underconditions such that the volume fof residual oil gas produced `per gallon o f petroleum oil pyro- `lyzerl falls within the range of from 40 .to 65 cubic feet taken as if measured at a pressure of '160 mm. and a temperature of 60 F., and such that the Irelationship between the sulfonation residue and the free carbon obtained is within the sulionationresidue-free carbon relationships lying to the left of and below the curve denned by the are respectively rectangular coordinates ci free carbon expressed in percent by weight' of the original oil pyrolyzed. and sulionation residue expressed in percent by volume o! the originaloil pyrolyzcd.

15..A process for the production in relatively high proportion and in good quality of resinsteps of pyrolyzing in said gas-making path a I' io unsaturated aromatic hydrocarbons invciu resin-forming aromatic hydrocarbons boiling above 200 C. and of other aromatic hydrocarbons in good quality, which comprises pyrolyzing a petroleum oil selected from the group consisting of petroleum oils of below 7% in Conrn carbon and f within the classifications of from 5 to ,7 inclusive as determined by the Bureau of Mines index and fractions from rolyzedi'alls within .the range of from 45 to 65 cubic feet taken as if measured at a pressure' ci '160 mm. and at a temperature o! 60 F., and such that the relationship between the sulfonation residue and the i'ree carbon obtained is within the suli'onation residue-tree carbon relationships lying to the left of and below the curve defined by the equation PNY-0.03) =0.03 in which X and Y are respectively rectangular coordinates of free carbon 4expressed in percent by yweight of the original. oil pyrolyzed and oi' sultonation lresidue expressed in percent byvolume oil pyrolyaed. 14. A process for the production in relatively high proportion and in good 'quality of resinforming unsaturated aromatic hydrocarbons inv cluding resin-forming unsaturated aromatic hydrocarbons boiling above 200 C. and 'non-resinforming aromatic hydrocarbons in .good quality and the. free carbon obtained is wit e are respectively rectangular coordinates of tree carbon expressed in percent by weight of the original oil pyrolyzed and o i sulionation residue expressed in percent`Y by'volume or the or :el

oil pyrolyaed, condensingl hydrocarbons includ ing said resin-forming aromatic hydrocarbon pf the original which comprises pyrolyzing in vapor phase in the presence of added benzene and in themes-- ence oi a substantial proportion of team' a p'eti'of num ou having an average boiling point-densityis phase with an intensity or emma auch that the material boiling above.200 C. from .the gas resulting from said pyrolysis, and recovering from the resulting condensate a dead oil fraction in which said resin-forming' aromatic hydrocarbon material boiling above 200 C. is concentrated.

16. A process for the production in relatively hifh proportion and in good quality o! resinforming unsaturated aromatic hydrocarbons including resin-forming unsaturated aromatic hy drocarbons boiling. above 200I C. and alkenatedaromatic hydrocarbons and ot other aromatic hy.-

drocarbons in good quality, which comprises pyrol lysing' a petroleum oil selected from the. group consisting o! petroleumv oils of below 7% in Con- 'radsoncarbon and iallingwithin theV classitications ot from 5 to 1 inclusive as determined blthe. i Bureau of Mines Index and fractions from said petroleum oils'. conducting said pyrolysis in vapor 

